I like to see what's going to be installed before it's installed. Seeing gobs of OLE and DLL files I worried your installer was going to scatter them around, or at least place them outside the Pico directory. As such I used WinRar to extract them and received a decompression error:

Plugin Commander installs some files in the System folder. Many of these files are also needed by other applications and probably already there. In such cases they are not installed. Anyway, if you uninstall Plugin Commander again most of them (except those needed by other applications) will be removed again.